Operational Amplifiers

Size: px
Start display at page:

Download "Operational Amplifiers"

Transcription

1 IRWI04_133164v3 8/30/04 3:29 PM Page 133 Operational Amplifiers 4 4LEARNING GOALS In this chapter we discuss a very important commercially available circuit known as the operational amplifier, or opamp. Opamps are used in literally thousands of applications, including such things as compact disk (CD) players, random access memories (RAMs), analogtodigital (A/D) and digitaltoanalog (D/A) converters, headphone amplifiers, and electronic instrumentation of all types. Finally, we discuss the terminal characteristics of this circuit and demonstrate its use in practical applications as well as circuit design. 4.1 Introduction A brief introduction is given to an extremely important electronic circuit known as the operational amplifier, or opamp...page OpAmp Models Models for the opamp are developed. This electronic circuit is characterized by highinput resistance, lowoutput resistance, and very high gain...page Fundamental OpAmp Circuits Basic opamp configurations, including inverting and noninverting circuits, are widely used in a host of practical applications...page Comparators A comparator is a variant of the opamp circuit that finds wide application in circuits where comparisons between two quantities are required...page Application Examples...Page Design Examples...Page 152 Summary...Page 155 Problems...Page 155 Access ProblemSolving Videos PSV and Circuit Solutions CS at: using the registration code on the inside cover and see a website with answers and more!

2 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS 4.1 Introduction Figure 4.1 A selection of opamps. On the left in (a) is a discrete opamp assembled on a printed circuit board (PCB). On the right, topdown, a LM324 DIP, LMC6492 DIP, and MAX4240 in a SO5 package (small outline/5 pins). The APEX PA03 with its lid removed (b) showing individual transistors and resistors. It can be argued that the operational amplifier, or opamp as it is commonly known, is the single most important integrated circuit for analog circuit design. It is a versatile interconnection of transistors and resistors that vastly expands our capabilities in circuit design, from engine control systems to cellular phones. Early opamps were built of vacuum tubes, making them bulky and power hungry. The invention of the transistor at Bell Labs in 1947 allowed engineers to create opamps that were much smaller and more efficient. Still, the opamp itself consisted of individual transistors and resistors interconnected on a printed circuit board (PCB). When the manufacturing process for integrated circuits (ICs) was developed around 1970, engineers could finally put all of the opamp transistors and resistors onto a single IC chip. Today, it is common to find as many as four highquality opamps on a single IC for as little as $0.40. A sample of commercial opamps is shown in Fig (a) (b) 4.2 OpAmp Models Why are they called operational amplifiers? Originally, the opamp was designed to perform mathematical operations such as addition, subtraction, differentiation, and integration. By adding simple networks to the opamp, we can create these building blocks as well as voltage scaling, currenttovoltage conversion, and a myriad of more complex applications. How can we, understanding only sources and resistors, hope to comprehend the performance of the opamp? The answer lies in modeling. When the bells and whistles are removed, an opamp is just a really good voltage amplifier. In other words, the output voltage is a scaled replica of the input voltage. Modern opamps are such good amplifiers that it is easy to create an accurate, firstorder model. As mentioned earlier, the opamp is very popular and is used extensively in circuit design at all levels. We should not be surprised to find that opamps are available for every application low voltage, high voltage, micropower, high speed, high current, and so forth. Fortunately, the topology of our model is independent of these issues. We start with the generalpurpose LM324 quad (four in a pack) opamp from National Semiconductor, shown in the upper right corner of Fig. 4.1a. The pinout for the LM324 is shown in Fig. 4.2 for a DIP (Dual Inline Pack) style package with dimensions in inches. Recognizing there are four identical opamps in the package, we will focus on amplifier 1. Pins 3 and 2 are the input pins, IN 1 and IN 1, and are called the noninverting and inverting inputs, respectively.

3 IRWI04_133164v3 8/30/04 3:29 PM Page 135 SECTION 4.2 OPAMP MODELS OUT 4 IN 4 IN 4 V EE IN 3 IN 3 IN Figure 4.2 The pinout (a) and dimensional diagram (b) of the LM324 quad opamp. Note the pin pitch (distance pintopin) is 0.1 inches standard for DIP packages OUT 1 IN 1 IN 1 V CC IN 2 IN 2 OUT (a) (b) The output is at pin 1. A relationship exists between the output and input voltages, = A o (IN IN ) 4.1 where all voltages are measured with respect to ground and A o is the gain of the opamp. (The location of the ground terminal will be discussed shortly.) From Eq. (4.1), we see that when IN increases, so will. However, if IN increases, then will decrease hence the names noninverting and inverting inputs. We mentioned earlier that opamps are very good voltage amplifiers. How good? Typical values for A o are between 10,000 and 1,000,000! Amplification requires power that is provided by the dc voltage sources connected to pins 4 and 11, called V CC and V EE, respectively. Figure 4.3 shows how the power supplies, or rails, are connected for both dual and singlesupply applications and defines the ground node to which all input and output voltages are referenced. Traditionally, V CC is a positive dc voltage with respect to ground, and V EE is either a negative voltage or ground itself. Actual values for these power supplies can vary widely depending on the application, from as little as one volt up to several hundred. How can we model the opamp? A dependent voltage source can produce! What about the currents into and out of the opamp terminals (pins 3, 2, and 1)? Fortunately for us, the currents are fairly proportional to the pin voltages. That sounds like Ohm s law. So, we model the IV performance with two resistors, one at the input terminals (R i ) and another at the output (R o ). The circuit in Fig. 4.4 brings everything together. V V IN CC CC IN out IN IN V EE V EE V CC V EE V CC Figure 4.3 Schematics showing the power supply connections and ground location for (a) dualsupply and (b) singlesupply implementations. (a) (b) R o Figure 4.4 A simple model for the gain characteristics of an opamp. IN (t) v in (t) IN (t) R i A o v in (t)

4 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS Figure 4.5 A network that depicts an opamp circuit. R Th1 R o S and R Th1 model the driving circuit, while the load is modeled by R L. The circuit in Fig. 4.4 is the opamp model. v in (t) R i A o v in R L (t) What values can we expect for A o, R i, and R o? We can reason through this issue with the help of Fig. 4.5 where we have drawn an equivalent for the circuitry that drives the input nodes and we have modeled the circuitry connected to the output with a single resistor, R L. Since the opamp is supposed to be a great voltage amplifier, let s write an equation for the overall gain of the circuit. Using voltage division at the input and again at the output, we quickly produce the expression R i = c d A o c d R i R Th1 R o R L To maximize the gain regardless of the values of R Th1 and R L, we make the voltage division ratios as close to unity as possible. The ideal scenario requires that A o be infinity, R i be infinity, and R o be zero, yielding a large overall gain of A o. Table 4.1 shows the actual values of A o, R i, and R o for a sampling of commercial opamps intended for very different applications. While A o, R i, and R o are not ideal, they do have the correct tendencies. The power supplies affect performance in two ways. First, each opamp has minimum and maximum supply ranges over which the opamp is guaranteed to function. Second, for proper operation, the input and output voltages are limited to no more than the supply voltages.* If the inputs/output can reach within a few dozen millivolts of the supplies, then the inputs/ output are called railtorail. Otherwise, the inputs/output voltage limits are more severe usually a volt or so away from the supply values. Combining the model in Fig. 4.4, the values in Table 4.1, and these I/O limitations, we can produce the graph in Fig. 4.6 showing the outputinput relation for each opamp in Table 4.1. From the graph we see that LMC6492 and MAX4240 have railtorail outputs while the LM324 and PA03 do not. R L Table 4.1 A list of commercial opamps and their model values Manufacturer Part No. ( V/V ) ( M ) ( ) Comments A o R i National LM , General purpose, up to ;16 V supplies, very inexpensive National LMC , Low voltage, railtorail inputs and outputs* Maxim MAX , Micropower (1.8 V 10 A), railtorail inputs and outputs Apex PA03 125, Highvoltage, ;75 V, and highoutput current capability, 30 A. That s 2 kw! *Railtorail is a trademark of Motorola Corporation. This feature is discussed further in the following paragraphs. R o Even though the opamp can function within the minimum and maximum supply voltages, because of the circuit configuration, an increase in the input voltage may not yield a corresponding increase in the output voltage. In this case, the opamp is said to be in saturation. The following example addresses this issue. *Opamps are available that have input and/or output voltage ranges beyond the supply rails. However, these devices constitute a very small percentage of the opamp market and will not be discussed here.

5 IRWI04_133164v3 8/30/04 3:29 PM Page 137 SECTION 4.2 OPAMP MODELS 137 Output voltage, (V) LM324@ / 15 V LMC6492@ / 5 V MAX4240@ / 1.5 V Input voltage, v in ( V) Output voltage, (V) LM324@ / 15 V MAX4240@ / 1.5 V PA03@ / 75 V LMC6492@ / 5 V Input voltage, v in (mv) Figure 4.6 Transfer plots for the opamps listed in Table 4.1. The supply voltages are listed in the plot legends. Note that the LMC6492 and MAX4240 have railtorail output voltages (output voltage range extends to power supply values), while the LM324 and PA03 do not. Example 4.1 The input and output signals for an opamp circuit are shown in Fig We wish to determine (a) if the opamp circuit is linear and (b) the circuit s gain. SOLUTION a. We know that if the circuit is linear, the output must be linearly related, that is, proportional, to the input. An examination of the input and output waveforms in Fig. 4.7 clearly indicates that in the region t = 1.25 to 2.5 and 4 to 6 ms the output is constant while the input is changing. In this case, the opamp circuit is in saturation and therefore not linear. b. In the region where the output is proportional to the input, that is, t = 0 to 1 ms, the input changes by 1 V and the output changes by 3.3 V. Therefore, the circuit s gain is 3.3. Voltage (V) 3 Output Figure 4.7 An opamp inputoutput characteristic Input Output Input t (ms) To introduce the performance of the opamp in a practical circuit, consider the network in Fig. 4.8a called a unity gain buffer. Notice that the opamp schematic symbol includes the power supplies. Substituting the model in Fig. 4.4 yields the circuit in Fig. 4.8b, containing just resistors and dependent sources, which we can easily analyze. Writing loop equations, we have = IR i IR o A o V in ut = IR o A o V in V in = IR i

6 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS Figure 4.8 Circuit (a) and model (b) for the unity gain buffer. V CC V EE V in R i A o V in I R o (a) (b) Solving for the gain,, we find For R o V R i, we have = 1 L 1 R i R o A o R i A o And, if A o is indeed W 1, L 1 The origin of the name unity gain buffer should be apparent. Table 4.2 shows the actual gain values for = 1 V using the opamps listed in Table 4.1. Notice how close the gain is to unity and how small the input voltage and current are. These results lead us to simplify the opamp in Fig. 4.4 significantly. We introduce the ideal opamp model, where A o and R i are infinite and R o is zero. This produces two important results for analyzing opamp circuitry, listed in Table 4.3. Table 4.2 Unity gain buffer performance for the opamps listed in Table 4.1 Table 4.3 Consequences of the ideal opamp model on input terminal I V values OpAmp Buffer Gain ( V) I( pa) V in LM LMC * 10 6 MAX PA * 10 5 Model Assumption A o Sq R i Sq Terminal Result input voltage S 0 V input current S 0 A v i v i Figure 4.9 Ideal model for an operational amplifier. Model parameters: i = i = 0, v = v. From Table 4.3 we find that the ideal model for the opamp is reduced to that shown in Fig The important characteristics of the model are as follows: (1) Since R i is extremely large, the input currents to the opamp are approximately zero (i.e., i L i L 0); and (2) if the output voltage is to remain bounded, then as the gain becomes very large and approaches infinity, the voltage across the input terminals must simultaneously become infinitesimally small so that as A o Sq, v v S 0 (i.e., v v = 0 or v = v ). The difference between these input voltages is often called the error signal for the opamp (i.e., v v = v e ). The ground terminal shown on the opamp is necessary for signal current return, and it guarantees that Kirchhoff s current law is satisfied at both the opamp and the ground node in the circuit.

7 IRWI04_133164v3 8/30/04 3:41 PM Page 139 SECTION 4.2 OPAMP MODELS 139 In summary, then, our ideal model for the opamp is simply stated by the following conditions: i = i = v = v 0 V 0 A V in 0 A These simple conditions are extremely important because they form the basis of our analysis of opamp circuits. Let s use the ideal model to reexamine the unity gain buffer, drawn again in Fig. 4.10, where the input voltage and currents are shown as zero. Given V in is zero, the voltage at both opamp inputs is. Since the inverting input is physically connected to the output, is also unity gain! Armed with the ideal opamp model, let s change the circuit in Fig slightly as shown in Fig where and R S are an equivalent for the circuit driving the buffer and R L models the circuitry connected to the output. There are three main points here. First, the gain is still unity. Second, the opamp requires no current from the driving circuit. Third, the output current (I o = R L ) comes from the power supplies, through the opamp and out of the output pin. In other words, the load current comes from the power supplies, which have plenty of current output capacity, rather than the driving circuit, which may have very little. This isolation of current is called buffering. An obvious question at this point is this: If =, why not just connect to via two parallel connection wires; why do we need to place an opamp between them? The answer to this question is fundamental and provides us with some insight that will aid us in circuit analysis and design. Consider the circuit shown in Fig. 4.12a. In this case is not equal to because of the voltage drop across : R S VS Figure 4.10 An ideal opamp configured as a unity gain buffer. = IR S However, in Fig. 4.12b, the input current to the opamp is zero and, therefore, appears at the opamp input. Since the gain of the opamp configuration is 1, =. In Fig. 4.12a the resistive network s interaction with the source caused the voltage to be less than. In other words, the resistive network loads the source voltage. However, in Fig. 4.12b the opamp isolates the source from the resistive network; therefore, the voltage follower is referred to as a buffer amplifier because it can be used to isolate one circuit from another. The energy supplied to the resistive network in the first case must come from the source, whereas in the second case it comes from the power supplies that supply the amplifier, and little or no energy is drawn from. R S 0 V 0 A 0 A V CC V EE I o Figure 4.11 A unity gain buffer with a load resistor. R L 1 k R S I Resistive network R S I Resistive network Figure 4.12 Illustration of the isolation capability of a voltage follower.

8 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS 4.3 Fundamental OpAmp Circuits As a general rule, when analyzing opamp circuits we write nodal equations at the opamp input terminals, using the ideal opamp model conditions. Thus, the technique is straightforward and simple to implement. Example 4.2 Let us determine the gain of the basic inverting opamp configuration shown in Fig. 4.13a using both the nonideal and ideal opamp models. b d A a c v S v i v i a b A c d (a) (b) a v v e b v R i R o A(v v ) =Av e c d v S b v Ri v c R o A(v v ) d vo (c) (d) v 1 v S R i v e Av e R o (e) Figure 4.13 Opamp circuit. SOLUTION Our model for the opamp is shown generically in Fig. 4.13b and specifically in terms of the parameters R i, A, and R o in Fig. 4.13c. If the model is inserted in the network in Fig. 4.13a, we obtain the circuit shown in Fig. 4.13d, which can be redrawn as shown in Fig. 4.13e.

9 IRWI04_133164v3 8/30/04 3:29 PM Page 141 SECTION 4.3 FUNDAMENTAL OPAMP CIRCUITS 141 The node equations for the network are v 1 v S v 1 R i v 1 = 0 v 1 Av e R o = 0 where v e =v 1. The equations can be written in matrix form as R i D a 1 A b R o v S a 1 b 1 1 TB v 1 R = C S 0 R o Solving for the node voltages, we obtain where 1 B v 1 R = 1 1 D R o 1 A R o R i 1 R o TC v S S 0 = a 1 1 R i 1 ba 1 1 R o b a 1 ba 1 A R o b Hence, = a 1 A R o ba v S b a 1 1 R i 1 ba 1 1 R o b a 1 ba 1 A R o b which can be written as A B = v S 1 c a ba 1 1 b n a 1 ba 1 A b d R i R o R o If we now employ typical values for the circuit parameters (e.g., A = 10 5, R o = 10, = 1 k, and = 5 k ), the voltage gain of the network is R i = 10 8, v S = L5.000 However, the ideal opamp has infinite gain. Therefore, if we take the limit of the gain equation as A Sq, we obtain lim A a b = =5.000 Sq v S Note that the ideal opamp yielded a result accurate to within four significant digits of that obtained from an exact solution of a typical opamp model. These results are easily repeated for the vast array of useful opamp circuits. We now analyze the network in Fig. 4.13a using the ideal opamp model. In this model i = i = 0 v = v

10 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS As shown in Fig. 4.13a, v = 0 and, therefore, v = 0. If we now write a node equation at the negative terminal of the opamp, we obtain or v S 0 0 = 0 v S = and we have immediately obtained the results derived previously. Notice that the gain is a simple resistor ratio. This fact makes the amplifier very versatile in that we can control the gain accurately and alter its value by changing only one resistor. Also, the gain is essentially independent of opamp parameters. Since the precise values of A o, R i, and R o are sensitive to such factors as temperature, radiation, and age, their elimination results in a gain that is stable regardless of the immediate environment. Since it is much easier to employ the ideal opamp model rather than the nonideal model, unless otherwise stated we will use the ideal opamp assumptions to analyze circuits that contain operational amplifiers. P ROBLEMSOLVING S TRATEGY OpAmp Circuits Step 1. Step 2. Step 3. Use the ideal opamp model: A o =q, R i =q, R o = 0. i = i = 0 v = v Apply nodal analysis to the resulting circuit. Solve nodal equations to express the output voltage in terms of the opamp input signals. Example 4.3 Let us now determine the gain of the basic noninverting opamp configuration shown in Fig Figure 4.14 The noninverting opamp configuration. v in R I R F SOLUTION Once again we employ the ideal opamp model conditions, that is, v = v and i = i. Using the fact that i = 0 and v = V in, the KCL equation at the negative terminal of the opamp is or Thus v in R I v in a 1 R I 1 R F b = R F v in = v in R F = 1 R F R I Note the similarity of this case to the inverting opamp configuration in the previous example. We find that the gain in this configuration is also controlled by a simple resistor ratio, but is not inverted; that is, the gain ratio is positive.

11 IRWI04_133164v3 8/30/04 3:29 PM Page 143 SECTION 4.3 FUNDAMENTAL OPAMP CIRCUITS 143 The remaining examples, though slightly more complicated, are analyzed in exactly the same manner as those outlined above. Example 4.4 Gain error in an amplifier is defined as We wish to show that for a standard noninverting configuration with finite gain A o, the gain error is GE = 100% 1 A o where = ( ). actual gain ideal gain GE = c d * 100% ideal gain SOLUTION The standard noninverting configuration and its equivalent circuit are shown in Fig. 4.15a and b, respectively. The circuit equations for the network in Fig. 4.15b are v S = v in v 1, v in = A o and v 1 = The expression that relates the input and output is = v S = c 1 A o d = c 1 A o d A o and thus the actual gain is v S = A o 1 A o Recall that the ideal gain for this circuit is ( ) = 1. Therefore, the gain error is which when simplified yields A o GE = 1 A o 1 100% 1 GE = 100% 1 A o v S v S v in A o v in Figure 4.15 Circuits used in Example 4.4. v 1 (a) (b)

12 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS Example 4.5 Consider the opamp circuit shown in Fig Let us determine an expression for the output voltage. Figure 4.16 Differential amplifier operational amplifier circuit. v i v 1 v 2 v R 3 i v R o 4 SOLUTION The node equation at the inverting terminal is At the noninverting terminal KCL yields However, i = i = 0 and v = v. Substituting these values into the two preceding equations yields v 1 v v = 0 and v 1 v v = i Solving these two equations for results in the expression = a 1 b v 2 v R 3 = v R 4 i v 2 v R 3 = v R 4 R 4 R 3 R 4 v 2 v 1 Note that if R 4 = and R 3 =, the expression reduces to = Av 2 v 1 B Therefore, this opamp can be employed to subtract two input voltages. Example 4.6 The circuit shown in Fig. 4.17a is a precision differential voltagegain device. It is used to provide a singleended input for an analogtodigital converter. We wish to derive an expression for the output of the circuit in terms of the two inputs. SOLUTION To accomplish this, we draw the equivalent circuit shown in Fig. 4.17b. Recall that the voltage across the input terminals of the opamp is approximately zero and the currents into the opamp input terminals are approximately zero. Note that we can write node

13 IRWI04_133164v3 8/30/04 3:29 PM Page 145 SECTION 4.3 FUNDAMENTAL OPAMP CIRCUITS 145 equations for node voltages v 1 and v 2 in terms of and v a. Since we are interested in an expression for in terms of the voltages v 1 and v 2, we simply eliminate the v a terms from the two node equations. The node equations are v 1 v 1 v a v 1 v 2 R G = 0 v 2 v a v 2 v 1 R G v 2 = 0 Combining the two equations to eliminate v a, and then writing in terms of v 1 and v 2, yields = Av 1 v 2 B a 1 2 R G b v 1 Figure 4.17 Instrumentation amplifier circuit. v 1 i 1 =0 v 1 v 2 v a R G v a R G v 2 i 2 =0 v 2 (a) (b) LEARNING EXTENSIONS E4.1 Find I o in the network in Fig. E4.1. PSV ANSWER: I o = 8.4 ma. Figure E k 12 V 10 k 2 k I o (continues on the next page)

14 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS E4.2 Determine the gain of the opamp circuit in Fig. E4.2. PSV Figure E4.2 ANSWER: = 1. Vo E4.3 Determine both the gain and the output voltage of the opamp configuration shown in Fig. E4.3. ANSWER: = V; gain=101. Figure E4.3 1 mv 100 k 1 k Example 4.7 The two opamp circuits shown in Fig produce an output given by the equation = 8V 1 4 V 2 where 1 V V 1 2 V and 2 V V 2 3 V We wish to determine (a) the range of and (b) if both of the circuits will produce the full range of given that the dc supplies are ;10 V. SOLUTION a. Given that = 8 V 1 4 V 2 and the range for both V 1 and V 2 as 1 V V 1 2 V and 2 V V 2 3 V, we find that max = 8(2) 4(2) = 8 V and min = 8(1) 4(3) =4 V and thus the range of is 4 V to 8 V. b. Consider first the network in Fig. 4.18a. The signal at V x, which can be derived using the network in Example 4.5, is given by the equation V x = 2 V 1 V 2. V x is a maximum when V 1 = 2 V and V 2 = 2 V, that is, V x max = 2(2) 2 = 2 V. The minimum value for V x occurs when V 1 = 1 V and V 2 = 3 V, that is V x min = 2(1) 3 =1 V. Since both the max and min values are within the supply range of ;10 V, the first opamp in Fig. 4.18a will not saturate. The output of the second opamp in this circuit is given by the expression

15 IRWI04_133164v3 8/30/04 3:29 PM Page 147 SECTION 4.4 COMPARATORS 147 = 4V x. Therefore, the range of is 4 V 8 V. Since this range is also within the power supply voltages, the second opamp will not saturate, and this circuit will produce the full range of. Next, consider the network in Fig. 4.18b. The signal V y =8V 1 and so the range of V y is 16 V V y 8 V and the range of V y is outside the power supply limits. This circuit will saturate and fail to produce the full range of. V 1 V x Figure 4.18 Circuits used in Example k 10 k 10 k 30 k V 2 (a) 80 k V 1 10 k V y 10 k 10 k V 2 V z 10 k 10 k 30 k (b) 4.4 Comparators A comparator, a variant of the opamp, is designed to compare the noninverting and inverting input voltages. As shown in Fig. 4.19, when the noninverting input voltage is greater, the output goes as high as possible, at or near V CC. On the other hand, if the inverting input voltage is greater, the output goes as low as possible, at or near V EE. Of course, an ideal opamp can do the same thing, that is, swing the output voltage as far as possible. However, opamps are not designed to operate with the outputs saturated, whereas comparators are. As a result, comparators are faster and less expensive than opamps. We will present two very different quad comparators in this text, National Semiconductor s LM339 and Maxim s MAX917. Note that the LM339 requires a resistor, called a pullup resistor, connected between the output pin and V CC. The salient features of these products are listed in Table 4.4. From Table 4.4, it is easy to surmise that the LM339 is a generalpurpose comparator, whereas the MAX917 is intended for lowpower applications such as handheld products.

16 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS Figure 4.19 (a) An ideal comparator and (b) its transfer curve. V v in V V CC V EE Output voltage V CC 0 V EE Input voltage (V V ) (a) (b) A common comparator application is the zerocrossing detector, shown in Fig. 4.20a using a LM339 with ;5 V supplies. As seen in Fig. 4.20b, when is positive, should be near 5 V and when is negative, should be near 5 V. The output changes value on every zero crossing! Table 4.4 A listing of some of the features of the LM339 and MAX917 comparators Product Min. Supply Max. Supply Supply Current Max. Output Current Typical LM339 2 V 36 V 3 ma 50 ma 3 k MAX V 5.5 V 0.8 A 8 ma NA R pull up Figure 4.20 (a) A zerocrossing detector and (b) the corresponding input/output waveforms. 5 V 5 V 3 k I/O voltages (V) Input Output 6 Time (a) (b) 4.5 Application Examples At this point, we have a new element, the opamp, which we can effectively employ in both applications and circuit design. This device is an extremely useful element that vastly expands our capability in these areas. Because of its ubiquitous nature, the addition of the opamp to our repertoire of circuit elements permits us to deal with a wide spectrum of practical circuits. Thus, we will employ it here, and also use it throughout this text.

17 IRWI04_133164v3 8/30/04 3:29 PM Page 149 SECTION 4.5 APPLICATION EXAMPLES 149 Application Example 4.8 In a light meter, a sensor produces a current proportional to the intensity of the incident radiation. We wish to obtain a voltage proportional to the light s intensity using the circuit in Fig Thus, we select a value of R that will produce an output voltage of 1 V for each 10 A of sensor current. Assume the sensor has zero resistance. R Figure 4.21 Light intensity to voltage converter. Incident light I Light sensor SOLUTION Applying KCL at the opamp input, I = R Since V is 10 5 o I, R = 100 k Application Example 4.9 The circuit in Fig is an electronic ammeter. It operates as follows: The unknown current, I through R I produces a voltage, V I. V I is amplified by the opamp to produce a voltage,, which is proportional to I. The output voltage is measured with a simple voltmeter. We want to find the value of such that 10 V appears at for each milliamp of unknown current. SOLUTION Since the current into the opamp terminal is zero, the relationship between and I is V I = IR I V I I Unknown current Voltmeter Figure 4.22 Electronic ammeter. V I R I =1 k =1 k

18 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS The relationship between the input and output voltages is or, solving the equation for I, we obtain = V I a 1 b I = R I a 1 b Using the required ratio f 10 4 o I and resistor values from Fig. 4.22, we can find that = 9 k Application Example 4.10 Let us return to the dc motor control example in Chapter 3 (Example 3.22). We want to define the form of the power amplifier that reads the speed control signal, V speed and outputs the dc motor voltage with sufficient current to drive the motor as shown in Fig Let us make our selection under the condition that the total power dissipation in the amplifier should not exceed 100 mw. 5 V R pot =0 =1 V speed Power amp V M /V speed =4 V M dc motor Figure 4.23 The dc motor example from Chapter 3. SOLUTION From Table 4.1 we find that the only opamp with sufficient output voltage that is, a maximum output voltage of (4)(5) = 20 V for this application is the PA03 from APEX. Since the required gain is 4, we can employ the standard noninverting amplifier configuration shown in Fig If the PA03 is assumed to be ideal, then V M = V speed c 1 R B R A d = 4V speed There are, of course, an infinite number of solutions that will satisfy this equation. In order to select reasonable values, we should consider the possibility of high currents in R A and R B when V M is at its peak value of 20 V. Assuming that R in for the PA03 is much greater than R A, the currents in and essentially determine the total power dissipated. R B R A 5 V V speed R A R B V M Figure 4.24 The power amplifier configuration using the PA03 opamp.

19 IRWI04_133164v3 8/30/04 3:29 PM Page 151 SECTION 4.5 APPLICATION EXAMPLES 151 The total power dissipated in and is Since the total power should not exceed 100 mw, we can use 1 4 W resistors an inexpensive industry standard with room to spare. With this power specification, we find that Also, since R A P total = then R B = 3 R A. Combining this result with the power specification yields R A = 1 k and R B = 3 k. Both are standard 5% tolerance values. Application Example 4.11 R B V 2 M R A R B 202 R A R B = R A R B = V2 M P total = = R B R A = 4 An instrumentation amplifier of the form shown in Fig has been suggested. This amplifier should have highinput resistance, achieve a voltage gain (V 1 V 2 ) of 10, employ the MAX4240 opamp listed in Table 4.1, and operate from two 1.5 V AA cell batteries in series. Let us analyze this circuit, select the resistor values, and explore the validity of this configuration. 400 R A R B 1.5 V 1.5 V 3 V Differential amplifier 3 V 3 V R V x A V 1 A R B =R A R B R A R B =R A V y V 2 3 V Figure 4.25 An instrumentation amplifier using the MAX4240 opamp. SOLUTION As indicated, the opamp on the right side of the circuit is connected in the traditional differential amplifier configuration. Example 4.5 indicates that the voltage gain for this portion of the network is And if R A = R B, the equation reduces to = (V x V y )c R B R A d = V x V y If we can find a relationship between V 1, V 2, and V x and V y, then an expression for the overall voltage can be written. Applying KCL at node A yields or V 1 V 2 R = V x V 1 V x = V 1 c 1 R d V 2 c R d

20 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS In a similar manner, at node B we obtain or V 1 V 2 R = V 2 V y V y =V 1 c R d V 2 c 1 R d By combining these equations, the output voltage can be expressed as = V x V y = V 1 c 1 R d V 2 c R d V 1 c R d V 2 c 1 R d If the resistors are selected such that =, then the voltage gain is = 1 2 V 1 V 2 R For a gain of 10, we set = 4.5 R. To maintain low power, we will use fairly large values for these resistors. We somewhat arbitrarily choose R = 100 k and = = 450 k. We can use 100 k resistors in the differential amplifier stage as well. Note that the voltage gain of the instrumentation amplifier is essentially the same as that of a generic differential amplifier. So why add the additional cost of two more opamps? In this configuration the inputs V 1 and V 2 are directly connected to opamp input terminals; therefore, the input resistance of the intrumentation amplifier is extremely large. From Table 4.1 we see that R in for the MAX4240 is 45 M. This is not the case in the traditional differential amplifier where the external resistor can significantly decrease the input resistance. 4.6 Design Examples Design Example 4.12 We are asked to construct an amplifier that will reduce a very large input voltage (i.e., V in ranges between ;680 V) to a small output voltage in the range <5 V. Using only two resistors, we wish to design the best possible amplifier. SOLUTION Since we must reduce 680 V to 5 V, the use of an inverting amplifier seems to be appropriate. The input/output relationship for the circuit shown in Fig is V in = Since the circuit must reduce the voltage, must be much larger than. By trial and error, one excellent choice for the resistor pair, selected from the standard Table 2.1, is = 27 k and = 200. For a V in = 680 V, the resulting output voltage is V, resulting in a percent error of only 0.74%. Figure 4.26 A standard inverting amplifier stage. I V in

21 IRWI04_133164v3 8/30/04 3:29 PM Page 153 SECTION 4.6 DESIGN EXAMPLES 153 Design Example 4.13 There is a requirement to design a noninverting opamp configuration with two resistors under the following conditions: the gain must be 10, the input range is ;2 V, and the total power consumed by the resistors must be less than 100 mw. SOLUTION For the standard noninverting configuration in Fig. 4.27a, the gain is For a gain of 10, we find = 9. If = 3 k and = 27 k, then the gain requirement is met exactly. Obviously, a number of other choices can be made, from the standard Table 2.1, with a 3 27 ratio. The power limitation can be formalized by referring to Fig. 4.27b where the maximum input voltage (2 V) is applied. The total power dissipated by the resistors is The minimum value for P R = 22 is 400. V in = 1 (20 2)2 = V in 2 V 2 V =20 V Figure 4.27 The noninverting opamp configuration employed in Example (a) (b) Design Example 4.14 We wish to design a weightedsummer circuit that will produce the output The design specifications call for use of one opamp and no more than three resistors. Furthermore, we wish to minimize power while using resistors no larger than 10 k. SOLUTION A standard weightedsummer configuration is shown in Fig Our problem is reduced to finding values for the three resistors in the network. Using KCL, we can write where Combining there relationships yields =0.9V 1 0.1V 2 I 1 I 2 = R I 1 = V 1 and I 2 = V 2 =c R d V 1 c R d V 2 Therefore, we require R = 0.9 and R = 0.1

22 IRWI04_133164v3 8/30/04 3:29 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS I1 R I2 V 1 V 2 Figure 4.28 A standard weightedsummer configuration. From these requirements, we see that the largest resistor is and that R is the smallest. Also, note that the R ratio can be expressed as Finally, to minimize power, we should use the largest possible resistor values. Based on this information, the best resistor values are R = 270, = 300, and = 2.7 k, which yield the desired performance exactly. Design Example 4.15 In Example 2.36, a 250 resistor was used to convert a current in the 4 to 20mA range to a voltage such that a 20mA input produced a 5utput. In this case, the minimum current (4 ma) produces a resistor voltage of 1 V. Unfortunately, many control systems operate on a 0 to 5V range rather than a 1 to 5V range. Let us design a new converter that will output 0 V at 4 ma and 5 V at 20 ma. SOLUTION The simple resistor circuit we designed in Example 2.36 is a good start. However, the voltage span is only 4 V rather than the required 5 V, and the minimum value is not zero. These facts imply that a new resistor value is needed and the output voltage should be shifted down so that the minimum is zero. We begin by computing the necessary resistor value. R = V max V min I max I min = The resistor voltage will now range from (0.004)(312.5) to (0.02)(312.5) or 1.25 to 6.25 V. We must now design a circuit that shifts these voltage levels so that the range is 0 to 5 V. One possible option for the level shifter circuit is the differential amplifier shown in Fig Recall that the output voltage of this device is = (V I V shift ) = Differential amplifier with shifter 420 ma R V I R 2 V shift Figure 4.29 A 420 ma to 05 V converter circuit.

23 IRWI04_133164v3 8/30/04 3:30 PM Page 155 PROBLEMS 155 Since we have already chosen R for a voltage span of 5 V, the gain of the amplifier should be 1 (i.e., = ). Clearly, the value of the required shift voltage is 1.25 V. However, we can verify this value by inserting the minimum values into this last equation and find 0 = [(312.5)(0.004) V shift ] V shift = (312.5)(0.004) = 1.25 V There is one caveat to this design. We don t want the converter resistor, R, to affect the differential amplifier, or vice versa. This means that the vast majority of the 420 ma current should flow entirely through R and not through the differential amplifier resistors. If we choose and W R, this requirement will be met. Therefore, we might select = = 100 k so that their resistance values are more than 300 times that of R. SUMMARY Opamps are characterized by Highinput resistance Lowoutput resistance Very high gain The ideal opamp is modeled using i = i = 0 Opamp problems are typically analyzed by writing node equations at the opamp input terminals The output of a comparator is dependent on the difference in voltage at the input terminals v = v PSV CS PROBLEMS both available on the web at: SECTION An amplifier has a gain of 15 and the input waveform shown in Fig. P4.1. Draw the output waveform. v in (mv) (V) t (s) t (ms) Figure P An amplifier has a gain of 5 and the output waveform shown in Fig. P4.2. Sketch the input waveform. 12 Figure P4.2

24 IRWI04_133164v3 8/30/04 3:30 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS 4.3 An opamp base amplifier has supply voltages of ;5 V and a gain of 20. (a) Sketch the input waveform from the output waveform in Fig. P4.3. (b) Double the amplitude of your results in (a) and sketch the new output waveform. (V) Figure P t (ms) 4.4 For an ideal opamp, the voltage gain and input resistance are infinite while the output resistance is zero. What are the consequences for (a) the opamp s input voltage? (b) the opamp s input currents? (c) the opamp s output current? 4.5 Revisit your answers in Problem 4.4 under the following nonideal scenarios. (a) R in =q, R out = 0, A o Zq. (b) R in =q, R out 7 0, A o =q. (c) R in Zq, R out = 0, A o =q. 4.6 Revisit the exact analysis of the inverting configuration in Section 4.3. (a) Find an expression for the gain if R in =q, R out = 0, A o Zq. (b) Plot the ratio of the gain in (a) to the ideal gain versus A o for 1 A o 1000 for an ideal gain of 10. (c) From your plot, does the actual gain approach the ideal value as A o increases or decreases? (d) From your plot, what is the minimum value of A o if the actual gain is within 5% of the ideal case? 4.7 Revisit the exact analysis of the inverting amplifier in Section 4.3. (a) Find an expression for the voltage gain if R in Zq, R out = 0, A o Zq. (b) For = 27 k and = 3 k, plot the ratio of the actual gain to the ideal gain for A o = 1000 and 1 k R in 100 k. (c) From your plot, does the ratio approach unity as R in increases or decreases? (d) From your plot in (b), what is the minimum value of if the gain ratio is to be at least 0.98? R in 4.8 An opamp based amplifier has ;18 V supplies and a gain of 80. Over what input range is the amplifier linear? SECTION Determine the gain of the amplifier in Fig. P4.9. What is the value of I o? I o =20 kω V in =3.3 kω V in =2 V 4.10 For the amplifier in Fig. P4.10, find the gain and I o. I o =20 kω =3.3 kω =2 V Figure P4.9 Figure P4.10

25 IRWI04_133164v3 8/30/04 3:30 PM Page 157 PROBLEMS Using the ideal opamp assumptions, determine the values of and in Fig. P4.11. I 1 I 1 11 V 4.15 The opamp in the amplifier in Fig. P4.15 operates with ;15 V supplies and can output no more than 200 ma. What is the maximum gain allowable for the amplifier if the maximum value of is 1 V? Io =10 kω Vo 1 k 10 k R L 50 Figure P Using the ideal opamp assumptions, determine I 1, I 2, and I 3 in Fig. P4.12. PSV 1 ma Figure P In a useful application, the amplifier drives a load. The circuit in Fig. P4.13 models this scenario. (a) Sketch the gain for 10 R L q. (b) Sketch I o for 10 R L q if = 0.1 V. (c) Repeat (b) if = 1.0 V. (d) What is the minimum value of R L if I o must be less than 100 ma for V? (e) What is the current I S if R L is 100? Repeat for R L = 10 k. I S I 1 R 1 I 2 I o I 3 R L =27 kω =3 kω Figure P For the amplifier in Fig. P4.16, the maximum value of is 2 V and the opamp can deliver no more than 100 ma. (a) If ;10 V supplies are used, what is the maximum allowable value of? (b) Repeat for ;3 V supplies. (c) Discuss the impact of the supplies on the maximum allowable gain. I o V o Figure P For the circuit in Fig. P4.17, (a) find in terms of and V 2. (b) If V 1 = 2 V and V 2 = 6 V, find. V 1 R L R L =10 Ω =100 Ω (c) If the opamp supplies are ;12 V, and V 1 = 4 V, what is the allowable range of V 2? PSV V 1 Figure P Repeat Problem 4.13 for the circuit in Fig. P4.14. V 2 2 k 2 k 1 k =27 kω Io =3 kω Figure P4.17 R L Figure P4.14

26 IRWI04_133164v3 8/30/04 3:30 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS 4.18 Find in the circuit in Fig. P4.18 assuming the opamp 4.22 Find in the network in Fig. P4.22 and explain what is ideal. effect has on the output. 1 k 5 k 1 V 2 V 10 2 V 10 R o 1 Figure P The network in Fig. P4.19 is a currenttovoltage converter or transconductance amplifier. Find i S for this network. 1 Figure P Determine the expression for in the network in Fig. P4.23. i S Figure P Calculate the transfer function i o v 1 for the network shown in Fig. P4.20. v A v B Figure P4.23 v o 4.24 Show that the output of the circuit in Fig. P4.24 is = c 1 d V 1 V 2 v 1 i o V 1 R 3 R F Figure P4.20 R I R Determine the relationship between v 1 and i o in the circuit shown in Fig. P4.21. Figure P4.24 V 2 R F 4.25 Find in the network in Fig. P4.25. v 1 R I 4 i o 1 Figure P V 4 V Figure P4.25

27 IRWI04_133164v3 8/30/04 3:30 PM Page 159 PROBLEMS Find the voltage gain of the opamp circuit shown in Fig. P4.26. V 1 Figure P k 4.27 For the circuit in Fig find the value of that produces a voltage gain of k 24 k 1 k 4.30 Find in the circuit in Fig. P V Figure P Find in the circuit in Fig. P k 5 k 5 k 4 V 20 k 40 k Figure P Determine the relationship between and v in in the circuit in Fig. P4.28. v in V 1 R1 18 k 9 V Figure P Determine the expression for the output voltage,, of the inverting summer circuit shown in Fig. P4.32. v 1 10 V 100 k 20 k 30 k 12 V 40 k 20 k 6 V R F R I R F v 2 v 3 R 3 Figure P In the network in Fig. P4.29 derive the expression for in terms of the inputs and v 2. v 1 Figure P Determine the output voltage,, of the noninverting averaging circuit shown in Fig. P4.33. v 1 v 2 R F v 1 v 2 R I v 3 R 3 Figure P4.29 R I R F Figure P4.33

28 IRWI04_133164v3 8/30/04 3:30 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS 4.34 Find the input/output relationship for the current amplifier shown in Fig. P4.34. R F 4.37 Find the expression for in the differential amplifier circuit shown in Fig. P4.37. R F i in i o v 1 R L R I v 2 Figure P4.34 Figure P Find in the circuit in Fig. P k PSV 4.38 Find in the circuit in Fig. P4.38. R 3 PSV R 4 40 k 10 k v 1 5 V 20 k 40 k Figure P Find the output voltage,, in the circuit in Fig. P4.39. Figure P Find in the circuit in Fig. P4.36. v 1 R 4 R 3 v 1 R 1 v 2 v 2 R 3 R 4 Figure P4.36 Figure P4.39

29 IRWI04_133164v3 8/30/04 3:30 PM Page 161 PROBLEMS The electronic ammeter in Example 4.9 has been modified and is shown in Fig. P4.40. The selector switch allows the user to change the range of the meter. Using values for and from Example 4.9, find the values of R A and R B that will yield a 10utput when the current being measured is 100 ma and 10 ma, respectively Design an opampbased circuit to produce the function = 5 V 1 4 V Design an opampbased circuit to produce the function = 5 V 1 7 V 2 I Unknown current R A R B R C =1 k Voltmeter Selector switch =1 k =9 k Figure P Given a box of 10k resistors and an opamp, design a circuit that will have an output voltage of =2V 1 4V Design an opamp circuit that has a gain of 50 using resistors no smaller than 1 k Design a twostage opamp network that has a gain of 50,000 while drawing no current into its input terminal. Use no resistors smaller than 1 k Show that the circuit in Fig. P4.49 can produce the output = K 1 V 1 K 2 V 2 only for 0 K 1 K 2 1. V Design an opamp circuit that has the following input/output relationship: =5 V V 2 R 3 R A voltage waveform with a maximum value of 200 mv must be amplified to a maximum of 10 V and inverted. However, the circuit that produces the waveform can provide no more than 100 A. Design the required amplifier An amplifier with a gain of ; 1% is needed. Using resistor values from Table 2.1, design the amplifier. Use as few resistors as possible. Figure P4.49 V 2

30 IRWI04_133164v3 8/30/04 3:30 PM Page CHAPTER 4 OPERATIONAL AMPLIFIERS 4.50 A 170 C maximum temperature digester is used in a paper mill to process wood chips that will eventually become paper. As shown in Fig. P4.50a, three electronic thermometers are placed along its length. Each thermometer outputs 0 V at 0 C, and the voltage changes 25 mv C. We will use the average of the three thermometer voltages to find an aggregate digester temperature. Furthermore, 1 volt should appear at for every 10 C of average temperature. Design such an averaging circuit using the opamp configuration shown in Fig. 4.50b if the final output voltage must be positive. Paper mill digester 4.51 A 0.1 shunt resistor is used to measure current in a fuelcell circuit. The voltage drop across the shunt resistor is to be used to measure the current in the circuit. The maximum current is 20 A. Design the network shown in Fig. P4.51 so that a voltmeter attached to the output will read 0 volts when the current is 0 A and 20 V when the current is 20 A. Be careful not to load the shunt resistor, since loading will cause an inaccurate reading. Fuel cell Load Thermometer #1 Thermometer #2 Thermometer #3 0.1 Design circuit Voltmeter (a) Figure P4.51 R f R B V 1 V 2 V 3 R 3 R A V x (b) Figure P Wood pulp is used to make paper in a paper mill. The amount of lignin present in pulp is called the kappa number. A very sophisticated instrument is used to measure kappa, and the output of this instrument ranges from 1 to 5 volts, where 1 volt represents a kappa number of 12 and 5 volts represents a kappa number of 20. The pulp mill operator has asked to have a kappa meter installed on his console. Design a circuit that will employ as input the 1 to 5volt signal and output the kappa number. An electronics engineer in the plant has suggested the circuit shown in Fig. P V 24 V 24 V Figure P4.52

31 IRWI04_133164v3 8/30/04 3:30 PM Page 163 PROBLEMS ma 4.53 An operator in a chemical plant would like to have a set of indicator lights that indicate when a certain chemical flow is between certain specific values. The operator wants a RED light to indicate a flow of at least 10 GPM (gallons per minute), RED and YELLOW lights to indicate a flow of 60 GPM, and RED, YELLOW, and GREEN lights to indicate a flow rate of 80 GPM. The 420 ma flow meter instrument outputs 4 ma when the flow is zero and 20 ma when the flow rate is 100 GPM. An experienced engineer has suggested the circuit shown in Fig. P4.53. The 420 ma flow meter and 250 resistor provide a 15 V signal, which serves as one input for the three comparators. The light bulbs will turn on when the negative input to a comparator is higher than the positive input. Using this network, design a circuit that will satisfy the operator s requirements V 12 V Green 12 V according to the plot in Fig. P4.54a, is available. The problem then is to use this RTD to design a circuit that employs this device as an input and produces a 0 to 12V signal at the output, where 0 V corresponds to 0 C and 12 V corresponds to 500 C. An engineer familiar with this problem suggests the use of the circuit shown in Fig. P4.54b in which the RTD bridge circuit provides the input to a standard instrumentation amplifier. Determine the component values in this network needed to satisfy the design requirements. Resistance in ohms V 12 V Yellow Figure P4.54a Temperature in C R 3 R 5 R 4 R 6 Red 24 V v 1 V o (012V) R 5 Figure P V 24 V v 2 R An industrial plant has a requirement for a circuit that uses as input the temperature of a vessel and outputs a voltage proportional to the vessel s temperature. The vessel s temperature ranges from 0 C to 500 C, and the corresponding output of the circuit should range from 0 to 12 V. A RTD (resistive thermal device), which is a linear device whose resistance changes with temperature RTD Figure P4.54b R 3 R 4 R 5 R G

How To Calculate The Power Gain Of An Opamp

How To Calculate The Power Gain Of An Opamp A. M. Niknejad University of California, Berkeley EE 100 / 42 Lecture 8 p. 1/23 EE 42/100 Lecture 8: Op-Amps ELECTRONICS Rev C 2/8/2012 (9:54 AM) Prof. Ali M. Niknejad University of California, Berkeley

More information

Basic Op Amp Circuits

Basic Op Amp Circuits Basic Op Amp ircuits Manuel Toledo INEL 5205 Instrumentation August 3, 2008 Introduction The operational amplifier (op amp or OA for short) is perhaps the most important building block for the design of

More information

School of Engineering Department of Electrical and Computer Engineering

School of Engineering Department of Electrical and Computer Engineering 1 School of Engineering Department of Electrical and Computer Engineering 332:223 Principles of Electrical Engineering I Laboratory Experiment #4 Title: Operational Amplifiers 1 Introduction Objectives

More information

Chapter 19 Operational Amplifiers

Chapter 19 Operational Amplifiers Chapter 19 Operational Amplifiers The operational amplifier, or op-amp, is a basic building block of modern electronics. Op-amps date back to the early days of vacuum tubes, but they only became common

More information

Analog Signal Conditioning

Analog Signal Conditioning Analog Signal Conditioning Analog and Digital Electronics Electronics Digital Electronics Analog Electronics 2 Analog Electronics Analog Electronics Operational Amplifiers Transistors TRIAC 741 LF351 TL084

More information

OPERATIONAL AMPLIFIERS

OPERATIONAL AMPLIFIERS INTRODUCTION OPERATIONAL AMPLIFIERS The student will be introduced to the application and analysis of operational amplifiers in this laboratory experiment. The student will apply circuit analysis techniques

More information

Conversion Between Analog and Digital Signals

Conversion Between Analog and Digital Signals ELET 3156 DL - Laboratory #6 Conversion Between Analog and Digital Signals There is no pre-lab work required for this experiment. However, be sure to read through the assignment completely prior to starting

More information

MAS.836 HOW TO BIAS AN OP-AMP

MAS.836 HOW TO BIAS AN OP-AMP MAS.836 HOW TO BIAS AN OP-AMP Op-Amp Circuits: Bias, in an electronic circuit, describes the steady state operating characteristics with no signal being applied. In an op-amp circuit, the operating characteristic

More information

Chapter 7 Direct-Current Circuits

Chapter 7 Direct-Current Circuits Chapter 7 Direct-Current Circuits 7. Introduction...7-7. Electromotive Force...7-3 7.3 Resistors in Series and in Parallel...7-5 7.4 Kirchhoff s Circuit Rules...7-7 7.5 Voltage-Current Measurements...7-9

More information

Chapter 12: The Operational Amplifier

Chapter 12: The Operational Amplifier Chapter 12: The Operational Amplifier 12.1: Introduction to Operational Amplifier (Op-Amp) Operational amplifiers (op-amps) are very high gain dc coupled amplifiers with differential inputs; they are used

More information

LM 358 Op Amp. If you have small signals and need a more useful reading we could amplify it using the op amp, this is commonly used in sensors.

LM 358 Op Amp. If you have small signals and need a more useful reading we could amplify it using the op amp, this is commonly used in sensors. LM 358 Op Amp S k i l l L e v e l : I n t e r m e d i a t e OVERVIEW The LM 358 is a duel single supply operational amplifier. As it is a single supply it eliminates the need for a duel power supply, thus

More information

Use and Application of Output Limiting Amplifiers (HFA1115, HFA1130, HFA1135)

Use and Application of Output Limiting Amplifiers (HFA1115, HFA1130, HFA1135) Use and Application of Output Limiting Amplifiers (HFA111, HFA110, HFA11) Application Note November 1996 AN96 Introduction Amplifiers with internal voltage clamps, also known as limiting amplifiers, have

More information

Operational Amplifier - IC 741

Operational Amplifier - IC 741 Operational Amplifier - IC 741 Tabish December 2005 Aim: To study the working of an 741 operational amplifier by conducting the following experiments: (a) Input bias current measurement (b) Input offset

More information

LAB 7 MOSFET CHARACTERISTICS AND APPLICATIONS

LAB 7 MOSFET CHARACTERISTICS AND APPLICATIONS LAB 7 MOSFET CHARACTERISTICS AND APPLICATIONS Objective In this experiment you will study the i-v characteristics of an MOS transistor. You will use the MOSFET as a variable resistor and as a switch. BACKGROUND

More information

Lab 5 Operational Amplifiers

Lab 5 Operational Amplifiers Lab 5 Operational Amplifiers By: Gary A. Ybarra Christopher E. Cramer Duke University Department of Electrical and Computer Engineering Durham, NC. Purpose The purpose of this lab is to examine the properties

More information

OPERATIONAL AMPLIFIER

OPERATIONAL AMPLIFIER MODULE3 OPERATIONAL AMPLIFIER Contents 1. INTRODUCTION... 3 2. Operational Amplifier Block Diagram... 3 3. Operational Amplifier Characteristics... 3 4. Operational Amplifier Package... 4 4.1 Op Amp Pins

More information

Reading: HH Sections 4.11 4.13, 4.19 4.20 (pgs. 189-212, 222 224)

Reading: HH Sections 4.11 4.13, 4.19 4.20 (pgs. 189-212, 222 224) 6 OP AMPS II 6 Op Amps II In the previous lab, you explored several applications of op amps. In this exercise, you will look at some of their limitations. You will also examine the op amp integrator and

More information

Scaling and Biasing Analog Signals

Scaling and Biasing Analog Signals Scaling and Biasing Analog Signals November 2007 Introduction Scaling and biasing the range and offset of analog signals is a useful skill for working with a variety of electronics. Not only can it interface

More information

The Operational Amplfier Lab Guide

The Operational Amplfier Lab Guide EECS 100 Lab Guide Bharathwaj Muthuswamy The Operational Amplfier Lab Guide 1. Introduction COMPONENTS REQUIRED FOR THIS LAB : 1. LM741 op-amp integrated circuit (IC) 2. 1k resistors 3. 10k resistor 4.

More information

PHYSICS 111 LABORATORY Experiment #3 Current, Voltage and Resistance in Series and Parallel Circuits

PHYSICS 111 LABORATORY Experiment #3 Current, Voltage and Resistance in Series and Parallel Circuits PHYSCS 111 LABORATORY Experiment #3 Current, Voltage and Resistance in Series and Parallel Circuits This experiment is designed to investigate the relationship between current and potential in simple series

More information

Frequency Response of Filters

Frequency Response of Filters School of Engineering Department of Electrical and Computer Engineering 332:224 Principles of Electrical Engineering II Laboratory Experiment 2 Frequency Response of Filters 1 Introduction Objectives To

More information

Transistor Characteristics and Single Transistor Amplifier Sept. 8, 1997

Transistor Characteristics and Single Transistor Amplifier Sept. 8, 1997 Physics 623 Transistor Characteristics and Single Transistor Amplifier Sept. 8, 1997 1 Purpose To measure and understand the common emitter transistor characteristic curves. To use the base current gain

More information

Transistor Amplifiers

Transistor Amplifiers Physics 3330 Experiment #7 Fall 1999 Transistor Amplifiers Purpose The aim of this experiment is to develop a bipolar transistor amplifier with a voltage gain of minus 25. The amplifier must accept input

More information

Lab 7: Operational Amplifiers Part I

Lab 7: Operational Amplifiers Part I Lab 7: Operational Amplifiers Part I Objectives The objective of this lab is to study operational amplifier (op amp) and its applications. We will be simulating and building some basic op amp circuits,

More information

CHAPTER 28 ELECTRIC CIRCUITS

CHAPTER 28 ELECTRIC CIRCUITS CHAPTER 8 ELECTRIC CIRCUITS 1. Sketch a circuit diagram for a circuit that includes a resistor R 1 connected to the positive terminal of a battery, a pair of parallel resistors R and R connected to the

More information

Series and Parallel Resistive Circuits

Series and Parallel Resistive Circuits Series and Parallel Resistive Circuits The configuration of circuit elements clearly affects the behaviour of a circuit. Resistors connected in series or in parallel are very common in a circuit and act

More information

Basic voltmeter use. Resources and methods for learning about these subjects (list a few here, in preparation for your research):

Basic voltmeter use. Resources and methods for learning about these subjects (list a few here, in preparation for your research): Basic voltmeter use This worksheet and all related files are licensed under the Creative Commons ttribution License, version 1.0. To view a copy of this license, visit http://creativecommons.org/licenses/by/1.0/,

More information

Bipolar Transistor Amplifiers

Bipolar Transistor Amplifiers Physics 3330 Experiment #7 Fall 2005 Bipolar Transistor Amplifiers Purpose The aim of this experiment is to construct a bipolar transistor amplifier with a voltage gain of minus 25. The amplifier must

More information

Experiment #5, Series and Parallel Circuits, Kirchhoff s Laws

Experiment #5, Series and Parallel Circuits, Kirchhoff s Laws Physics 182 Summer 2013 Experiment #5 1 Experiment #5, Series and Parallel Circuits, Kirchhoff s Laws 1 Purpose Our purpose is to explore and validate Kirchhoff s laws as a way to better understanding

More information

DIGITAL-TO-ANALOGUE AND ANALOGUE-TO-DIGITAL CONVERSION

DIGITAL-TO-ANALOGUE AND ANALOGUE-TO-DIGITAL CONVERSION DIGITAL-TO-ANALOGUE AND ANALOGUE-TO-DIGITAL CONVERSION Introduction The outputs from sensors and communications receivers are analogue signals that have continuously varying amplitudes. In many systems

More information

Fundamentals of Microelectronics

Fundamentals of Microelectronics Fundamentals of Microelectronics CH1 Why Microelectronics? CH2 Basic Physics of Semiconductors CH3 Diode Circuits CH4 Physics of Bipolar Transistors CH5 Bipolar Amplifiers CH6 Physics of MOS Transistors

More information

Lab 3 - DC Circuits and Ohm s Law

Lab 3 - DC Circuits and Ohm s Law Lab 3 DC Circuits and Ohm s Law L3-1 Name Date Partners Lab 3 - DC Circuits and Ohm s Law OBJECTIES To learn to apply the concept of potential difference (voltage) to explain the action of a battery in

More information

Op amp DC error characteristics and the effect on high-precision applications

Op amp DC error characteristics and the effect on high-precision applications Op amp DC error characteristics and the effect on high-precision applications Srudeep Patil, Member of Technical Staff, Maxim Integrated - January 01, 2014 This article discusses the DC limitations of

More information

Measuring Electric Phenomena: the Ammeter and Voltmeter

Measuring Electric Phenomena: the Ammeter and Voltmeter Measuring Electric Phenomena: the Ammeter and Voltmeter 1 Objectives 1. To understand the use and operation of the Ammeter and Voltmeter in a simple direct current circuit, and 2. To verify Ohm s Law for

More information

BJT Characteristics and Amplifiers

BJT Characteristics and Amplifiers BJT Characteristics and Amplifiers Matthew Beckler beck0778@umn.edu EE2002 Lab Section 003 April 2, 2006 Abstract As a basic component in amplifier design, the properties of the Bipolar Junction Transistor

More information

Lecture Notes: ECS 203 Basic Electrical Engineering Semester 1/2010. Dr.Prapun Suksompong 1 June 16, 2010

Lecture Notes: ECS 203 Basic Electrical Engineering Semester 1/2010. Dr.Prapun Suksompong 1 June 16, 2010 Sirindhorn International Institute of Technology Thammasat University School of Information, Computer and Communication Technology Lecture Notes: ECS 203 Basic Electrical Engineering Semester 1/2010 Dr.Prapun

More information

Building the AMP Amplifier

Building the AMP Amplifier Building the AMP Amplifier Introduction For about 80 years it has been possible to amplify voltage differences and to increase the associated power, first with vacuum tubes using electrons from a hot filament;

More information

Current vs. Voltage Feedback Amplifiers

Current vs. Voltage Feedback Amplifiers Current vs. ltage Feedback Amplifiers One question continuously troubles the analog design engineer: Which amplifier topology is better for my application, current feedback or voltage feedback? In most

More information

Transistor Biasing. The basic function of transistor is to do amplification. Principles of Electronics

Transistor Biasing. The basic function of transistor is to do amplification. Principles of Electronics 192 9 Principles of Electronics Transistor Biasing 91 Faithful Amplification 92 Transistor Biasing 93 Inherent Variations of Transistor Parameters 94 Stabilisation 95 Essentials of a Transistor Biasing

More information

Temperature Sensors. Resistance Temperature Detectors (RTDs) Thermistors IC Temperature Sensors

Temperature Sensors. Resistance Temperature Detectors (RTDs) Thermistors IC Temperature Sensors Temperature Sensors Resistance Temperature Detectors (RTDs) Thermistors IC Temperature Sensors Drew Gilliam GE/MfgE 330: Introduction to Mechatronics 03.19.2003 Introduction There are a wide variety of

More information

Electronics. Discrete assembly of an operational amplifier as a transistor circuit. LD Physics Leaflets P4.2.1.1

Electronics. Discrete assembly of an operational amplifier as a transistor circuit. LD Physics Leaflets P4.2.1.1 Electronics Operational Amplifier Internal design of an operational amplifier LD Physics Leaflets Discrete assembly of an operational amplifier as a transistor circuit P4.2.1.1 Objects of the experiment

More information

The 2N3393 Bipolar Junction Transistor

The 2N3393 Bipolar Junction Transistor The 2N3393 Bipolar Junction Transistor Common-Emitter Amplifier Aaron Prust Abstract The bipolar junction transistor (BJT) is a non-linear electronic device which can be used for amplification and switching.

More information

Application Report SLOA030A

Application Report SLOA030A Application Report March 2001 Mixed Signal Products SLOA030A IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product

More information

Nodal and Loop Analysis

Nodal and Loop Analysis Nodal and Loop Analysis The process of analyzing circuits can sometimes be a difficult task to do. Examining a circuit with the node or loop methods can reduce the amount of time required to get important

More information

Figure 1. Diode circuit model

Figure 1. Diode circuit model Semiconductor Devices Non-linear Devices Diodes Introduction. The diode is two terminal non linear device whose I-V characteristic besides exhibiting non-linear behavior is also polarity dependent. The

More information

Cornerstone Electronics Technology and Robotics I Week 15 Voltage Comparators Tutorial

Cornerstone Electronics Technology and Robotics I Week 15 Voltage Comparators Tutorial Cornerstone Electronics Technology and Robotics I Week 15 Voltage Comparators Tutorial Administration: o Prayer Robot Building for Beginners, Chapter 15, Voltage Comparators: o Review of Sandwich s Circuit:

More information

Voltage/current converter opamp circuits

Voltage/current converter opamp circuits Voltage/current converter opamp circuits This worksheet and all related files are licensed under the Creative Commons Attribution License, version 1.0. To view a copy of this license, visit http://creativecommons.org/licenses/by/1.0/,

More information

Resistors in Series and Parallel

Resistors in Series and Parallel Resistors in Series and Parallel Bởi: OpenStaxCollege Most circuits have more than one component, called a resistor that limits the flow of charge in the circuit. A measure of this limit on charge flow

More information

THE BREADBOARD; DC POWER SUPPLY; RESISTANCE OF METERS; NODE VOLTAGES AND EQUIVALENT RESISTANCE; THÉVENIN EQUIVALENT CIRCUIT

THE BREADBOARD; DC POWER SUPPLY; RESISTANCE OF METERS; NODE VOLTAGES AND EQUIVALENT RESISTANCE; THÉVENIN EQUIVALENT CIRCUIT THE BREADBOARD; DC POWER SUPPLY; RESISTANCE OF METERS; NODE VOLTAGES AND EQUIVALENT RESISTANCE; THÉVENIN EQUIVALENT CIRCUIT YOUR NAME LAB MEETING TIME Reference: C.W. Alexander and M.N.O Sadiku, Fundamentals

More information

How To Close The Loop On A Fully Differential Op Amp

How To Close The Loop On A Fully Differential Op Amp Application Report SLOA099 - May 2002 Fully Differential Op Amps Made Easy Bruce Carter High Performance Linear ABSTRACT Fully differential op amps may be unfamiliar to some designers. This application

More information

Physics 623 Transistor Characteristics and Single Transistor Amplifier Sept. 13, 2006

Physics 623 Transistor Characteristics and Single Transistor Amplifier Sept. 13, 2006 Physics 623 Transistor Characteristics and Single Transistor Amplifier Sept. 13, 2006 1 Purpose To measure and understand the common emitter transistor characteristic curves. To use the base current gain

More information

LM118/LM218/LM318 Operational Amplifiers

LM118/LM218/LM318 Operational Amplifiers LM118/LM218/LM318 Operational Amplifiers General Description The LM118 series are precision high speed operational amplifiers designed for applications requiring wide bandwidth and high slew rate. They

More information

Dependent Sources: Introduction and analysis of circuits containing dependent sources.

Dependent Sources: Introduction and analysis of circuits containing dependent sources. Dependent Sources: Introduction and analysis of circuits containing dependent sources. So far we have explored timeindependent (resistive) elements that are also linear. We have seen that two terminal

More information

Lab E1: Introduction to Circuits

Lab E1: Introduction to Circuits E1.1 Lab E1: Introduction to Circuits The purpose of the this lab is to introduce you to some basic instrumentation used in electrical circuits. You will learn to use a DC power supply, a digital multimeter

More information

SERIES-PARALLEL DC CIRCUITS

SERIES-PARALLEL DC CIRCUITS Name: Date: Course and Section: Instructor: EXPERIMENT 1 SERIES-PARALLEL DC CIRCUITS OBJECTIVES 1. Test the theoretical analysis of series-parallel networks through direct measurements. 2. Improve skills

More information

Op-Amp Simulation EE/CS 5720/6720. Read Chapter 5 in Johns & Martin before you begin this assignment.

Op-Amp Simulation EE/CS 5720/6720. Read Chapter 5 in Johns & Martin before you begin this assignment. Op-Amp Simulation EE/CS 5720/6720 Read Chapter 5 in Johns & Martin before you begin this assignment. This assignment will take you through the simulation and basic characterization of a simple operational

More information

BIASING OF CONSTANT CURRENT MMIC AMPLIFIERS (e.g., ERA SERIES) (AN-60-010)

BIASING OF CONSTANT CURRENT MMIC AMPLIFIERS (e.g., ERA SERIES) (AN-60-010) BIASING OF CONSTANT CURRENT MMIC AMPLIFIERS (e.g., ERA SERIES) (AN-60-010) Introduction The Mini-Circuits family of microwave monolithic integrated circuit (MMIC) Darlington amplifiers offers the RF designer

More information

6.101 Final Project Proposal Class G Audio Amplifier. Mark Spatz

6.101 Final Project Proposal Class G Audio Amplifier. Mark Spatz 6.101 Final Project Proposal Class G Audio Amplifier Mark Spatz 1 1 Introduction For my final project, I will be constructing a 30V audio amplifier capable of delivering about 150 watts into a network

More information

Electrical Fundamentals Module 3: Parallel Circuits

Electrical Fundamentals Module 3: Parallel Circuits Electrical Fundamentals Module 3: Parallel Circuits PREPARED BY IAT Curriculum Unit August 2008 Institute of Applied Technology, 2008 ATE310- Electrical Fundamentals 2 Module 3 Parallel Circuits Module

More information

Series and Parallel Resistive Circuits Physics Lab VIII

Series and Parallel Resistive Circuits Physics Lab VIII Series and Parallel Resistive Circuits Physics Lab VIII Objective In the set of experiments, the theoretical expressions used to calculate the total resistance in a combination of resistors will be tested

More information

OPERATIONAL AMPLIFIERS. o/p

OPERATIONAL AMPLIFIERS. o/p OPERATIONAL AMPLIFIERS 1. If the input to the circuit of figure is a sine wave the output will be i/p o/p a. A half wave rectified sine wave b. A fullwave rectified sine wave c. A triangular wave d. A

More information

Programmable Single-/Dual-/Triple- Tone Gong SAE 800

Programmable Single-/Dual-/Triple- Tone Gong SAE 800 Programmable Single-/Dual-/Triple- Tone Gong Preliminary Data SAE 800 Bipolar IC Features Supply voltage range 2.8 V to 18 V Few external components (no electrolytic capacitor) 1 tone, 2 tones, 3 tones

More information

A Short Discussion on Summing Busses and Summing Amplifiers By Fred Forssell Copyright 2001, by Forssell Technologies All Rights Reserved

A Short Discussion on Summing Busses and Summing Amplifiers By Fred Forssell Copyright 2001, by Forssell Technologies All Rights Reserved A Short Discussion on Summing Busses and Summing Amplifiers By Fred Forssell Copyright 2001, by Forssell Technologies All Rights Reserved The summing network in mixing consoles is an easily misunderstood

More information

LABORATORY 2 THE DIFFERENTIAL AMPLIFIER

LABORATORY 2 THE DIFFERENTIAL AMPLIFIER LABORATORY 2 THE DIFFERENTIAL AMPLIFIER OBJECTIVES 1. To understand how to amplify weak (small) signals in the presence of noise. 1. To understand how a differential amplifier rejects noise and common

More information

www.jameco.com 1-800-831-4242

www.jameco.com 1-800-831-4242 Distributed by: www.jameco.com 1-800-831-4242 The content and copyrights of the attached material are the property of its owner. LF411 Low Offset, Low Drift JFET Input Operational Amplifier General Description

More information

Digital Energy ITI. Instrument Transformer Basic Technical Information and Application

Digital Energy ITI. Instrument Transformer Basic Technical Information and Application g Digital Energy ITI Instrument Transformer Basic Technical Information and Application Table of Contents DEFINITIONS AND FUNCTIONS CONSTRUCTION FEATURES MAGNETIC CIRCUITS RATING AND RATIO CURRENT TRANSFORMER

More information

Making Accurate Voltage Noise and Current Noise Measurements on Operational Amplifiers Down to 0.1Hz

Making Accurate Voltage Noise and Current Noise Measurements on Operational Amplifiers Down to 0.1Hz Author: Don LaFontaine Making Accurate Voltage Noise and Current Noise Measurements on Operational Amplifiers Down to 0.1Hz Abstract Making accurate voltage and current noise measurements on op amps in

More information

WHY DIFFERENTIAL? instruments connected to the circuit under test and results in V COMMON.

WHY DIFFERENTIAL? instruments connected to the circuit under test and results in V COMMON. WHY DIFFERENTIAL? Voltage, The Difference Whether aware of it or not, a person using an oscilloscope to make any voltage measurement is actually making a differential voltage measurement. By definition,

More information

Circuit Analysis using the Node and Mesh Methods

Circuit Analysis using the Node and Mesh Methods Circuit Analysis using the Node and Mesh Methods We have seen that using Kirchhoff s laws and Ohm s law we can analyze any circuit to determine the operating conditions (the currents and voltages). The

More information

GT Sensors Precision Gear Tooth and Encoder Sensors

GT Sensors Precision Gear Tooth and Encoder Sensors GT Sensors Precision Gear Tooth and Encoder Sensors NVE s GT Sensor products are based on a Low Hysteresis GMR sensor material and are designed for use in industrial speed applications where magnetic detection

More information

Lecture 18: Common Emitter Amplifier. Maximum Efficiency of Class A Amplifiers. Transformer Coupled Loads.

Lecture 18: Common Emitter Amplifier. Maximum Efficiency of Class A Amplifiers. Transformer Coupled Loads. Whites, EE 3 Lecture 18 Page 1 of 10 Lecture 18: Common Emitter Amplifier. Maximum Efficiency of Class A Amplifiers. Transformer Coupled Loads. We discussed using transistors as switches in the last lecture.

More information

6.101 Final Project Report Class G Audio Amplifier

6.101 Final Project Report Class G Audio Amplifier 6.101 Final Project Report Class G Audio Amplifier Mark Spatz 4/3/2014 1 1 Introduction For my final project, I designed and built a 150 Watt audio amplifier to replace the underpowered and unreliable

More information

Series and Parallel Circuits

Series and Parallel Circuits Direct Current (DC) Direct current (DC) is the unidirectional flow of electric charge. The term DC is used to refer to power systems that use refer to the constant (not changing with time), mean (average)

More information

ELECTRON SPIN RESONANCE Last Revised: July 2007

ELECTRON SPIN RESONANCE Last Revised: July 2007 QUESTION TO BE INVESTIGATED ELECTRON SPIN RESONANCE Last Revised: July 2007 How can we measure the Landé g factor for the free electron in DPPH as predicted by quantum mechanics? INTRODUCTION Electron

More information

Single Supply Op Amp Circuits Dr. Lynn Fuller

Single Supply Op Amp Circuits Dr. Lynn Fuller ROCHESTER INSTITUTE OF TECHNOLOGY MICROELECTRONIC ENGINEERING Single Supply Op Amp Circuits Dr. Lynn Fuller Webpage: http://people.rit.edu/lffeee 82 Lomb Memorial Drive Rochester, NY 146235604 Tel (585)

More information

RGB for ZX Spectrum 128, +2, +2A, +3

RGB for ZX Spectrum 128, +2, +2A, +3 RGB for ZX Spectrum 128, +2, +2A, +3 Introduction... 2 Video Circuitry... 3 Audio Circuitry... 8 Lead Wiring... 9 Testing The Lead... 11 Spectrum +2A/+3 RGB Differences... 12 Circuitry Calculations...

More information

Description. 5k (10k) - + 5k (10k)

Description. 5k (10k) - + 5k (10k) THAT Corporation Low Noise, High Performance Microphone Preamplifier IC FEATURES Excellent noise performance through the entire gain range Exceptionally low THD+N over the full audio bandwidth Low power

More information

Energy, Work, and Power

Energy, Work, and Power Energy, Work, and Power This worksheet and all related files are licensed under the Creative Commons Attribution License, version 1.0. To view a copy of this license, visit http://creativecommons.org/licenses/by/1.0/,

More information

LM386 Low Voltage Audio Power Amplifier

LM386 Low Voltage Audio Power Amplifier Low Voltage Audio Power Amplifier General Description The LM386 is a power amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count

More information

TEA1024/ TEA1124. Zero Voltage Switch with Fixed Ramp. Description. Features. Block Diagram

TEA1024/ TEA1124. Zero Voltage Switch with Fixed Ramp. Description. Features. Block Diagram Zero Voltage Switch with Fixed Ramp TEA04/ TEA4 Description The monolithic integrated bipolar circuit, TEA04/ TEA4 is a zero voltage switch for triac control in domestic equipments. It offers not only

More information

CALIBRATION OF A THERMISTOR THERMOMETER (version = fall 2001)

CALIBRATION OF A THERMISTOR THERMOMETER (version = fall 2001) CALIBRATION OF A THERMISTOR THERMOMETER (version = fall 2001) I. Introduction Calibration experiments or procedures are fairly common in laboratory work which involves any type of instrumentation. Calibration

More information

EGR 278 Digital Logic Lab File: N278L3A Lab # 3 Open-Collector and Driver Gates

EGR 278 Digital Logic Lab File: N278L3A Lab # 3 Open-Collector and Driver Gates EGR 278 Digital Logic Lab File: N278L3A Lab # 3 Open-Collector and Driver Gates A. Objectives The objectives of this laboratory are to investigate: the operation of open-collector gates, including the

More information

A Low-Cost VCA Limiter

A Low-Cost VCA Limiter The circuits within this application note feature THAT218x to provide the essential function of voltage-controlled amplifier (VCA). Since writing this note, THAT has introduced a new dual VCA, as well

More information

Basic RTD Measurements. Basics of Resistance Temperature Detectors

Basic RTD Measurements. Basics of Resistance Temperature Detectors Basic RTD Measurements Basics of Resistance Temperature Detectors Platinum RTD resistances range from about 10 O for a birdcage configuration to 10k O for a film type, but the most common is 100 O at 0

More information

Design of op amp sine wave oscillators

Design of op amp sine wave oscillators Design of op amp sine wave oscillators By on Mancini Senior Application Specialist, Operational Amplifiers riteria for oscillation The canonical form of a feedback system is shown in Figure, and Equation

More information

CA723, CA723C. Voltage Regulators Adjustable from 2V to 37V at Output Currents Up to 150mA without External Pass Transistors. Features.

CA723, CA723C. Voltage Regulators Adjustable from 2V to 37V at Output Currents Up to 150mA without External Pass Transistors. Features. CA73, CA73C Data Sheet April 1999 File Number 788. Voltage Regulators Adjustable from V to 37V at Output Currents Up to 1mA without External Pass Transistors The CA73 and CA73C are silicon monolithic integrated

More information

Constant Voltage and Constant Current Controller for Adaptors and Battery Chargers

Constant Voltage and Constant Current Controller for Adaptors and Battery Chargers TECHNICAL DATA Constant Voltage and Constant Current Controller for Adaptors and Battery Chargers IK3051 Description IK3051 is a highly integrated solution for SMPS applications requiring constant voltage

More information

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 4 - ALTERNATING CURRENT

EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 4 - ALTERNATING CURRENT EDEXCEL NATIONAL CERTIFICATE/DIPLOMA UNIT 5 - ELECTRICAL AND ELECTRONIC PRINCIPLES NQF LEVEL 3 OUTCOME 4 - ALTERNATING CURRENT 4 Understand single-phase alternating current (ac) theory Single phase AC

More information

Signal Conditioning Piezoelectric Sensors

Signal Conditioning Piezoelectric Sensors Application Report SLOA033A - September 2000 Signal Conditioning Piezoelectric Sensors James Karki Mixed Signal Products ABSTRACT Piezoelectric elements are used to construct transducers for a vast number

More information

Measurement of Capacitance

Measurement of Capacitance Measurement of Capacitance Pre-Lab Questions Page Name: Class: Roster Number: Instructor:. A capacitor is used to store. 2. What is the SI unit for capacitance? 3. A capacitor basically consists of two

More information

AP-1 Application Note on Remote Control of UltraVolt HVPS

AP-1 Application Note on Remote Control of UltraVolt HVPS Basics Of UltraVolt HVPS Output Voltage Control Application Note on Remote Control of UltraVolt HVPS By varying the voltage at the Remote Adjust Input terminal (pin 6) between 0 and +5V, the UV highvoltage

More information

CHAPTER 10 OPERATIONAL-AMPLIFIER CIRCUITS

CHAPTER 10 OPERATIONAL-AMPLIFIER CIRCUITS CHAPTER 10 OPERATIONAL-AMPLIFIER CIRCUITS Chapter Outline 10.1 The Two-Stage CMOS Op Amp 10.2 The Folded-Cascode CMOS Op Amp 10.3 The 741 Op-Amp Circuit 10.4 DC Analysis of the 741 10.5 Small-Signal Analysis

More information

Op Amp and Comparators Don t Confuse Them!

Op Amp and Comparators Don t Confuse Them! Application Report SLOA067 September 200 Op Amp and Comparators Don t Confuse Them! Bruce Carter High Performance Linear ABSTRACT Operational amplifiers (op amps) and comparators look similar; they even

More information

Features. Applications

Features. Applications LM555 Timer General Description The LM555 is a highly stable device for generating accurate time delays or oscillation. Additional terminals are provided for triggering or resetting if desired. In the

More information

Operational Amplifiers

Operational Amplifiers Module 6 Amplifiers Operational Amplifiers The Ideal Amplifier What you ll learn in Module 6. Section 6.0. Introduction to Operational Amplifiers. Understand Concept of the Ideal Amplifier and the Need

More information

DIODE CIRCUITS LABORATORY. Fig. 8.1a Fig 8.1b

DIODE CIRCUITS LABORATORY. Fig. 8.1a Fig 8.1b DIODE CIRCUITS LABORATORY A solid state diode consists of a junction of either dissimilar semiconductors (pn junction diode) or a metal and a semiconductor (Schottky barrier diode). Regardless of the type,

More information

Precision Diode Rectifiers

Precision Diode Rectifiers by Kenneth A. Kuhn March 21, 2013 Precision half-wave rectifiers An operational amplifier can be used to linearize a non-linear function such as the transfer function of a semiconductor diode. The classic

More information

ENEE 307 Electronic Circuit Design Laboratory Spring 2012. A. Iliadis Electrical Engineering Department University of Maryland College Park MD 20742

ENEE 307 Electronic Circuit Design Laboratory Spring 2012. A. Iliadis Electrical Engineering Department University of Maryland College Park MD 20742 1.1. Differential Amplifiers ENEE 307 Electronic Circuit Design Laboratory Spring 2012 A. Iliadis Electrical Engineering Department University of Maryland College Park MD 20742 Differential Amplifiers

More information

Application Note 142 August 2013. New Linear Regulators Solve Old Problems AN142-1

Application Note 142 August 2013. New Linear Regulators Solve Old Problems AN142-1 August 2013 New Linear Regulators Solve Old Problems Bob Dobkin, Vice President, Engineering and CTO, Linear Technology Corp. Regulators regulate but are capable of doing much more. The architecture of

More information